Breathing mask



FIG. 1 is a front perspective view of a breathing mask;

FIG. 2 is a front elevation view thereof;

FIG. 3 is a rear elevation view thereof;

FIG. 4 is a right side elevation view thereof;

FIG. 5 is a left side elevation view thereof;

FIG. 6 is a bottom plan view thereof;

FIG. 7 is a top plan view thereof;

FIG. 8 is a front perspective view with a port cap in an open position; and,

FIG. 9 is a front elevation view thereof with a port cap in an open position.

The broken lines in the drawings illustrate portions of the breathing mask and form no part of the claimed design.

The oblique line shading is used to denote claimed portions that are transparent or translucent. 

CLAIM The ornamental design for a breathing mask, as shown and described. 